Excellent Photocatalytic Performance For Degradation Research Articles

Threefold enhanced photodegradation of methylene blue using MgO composite with minimum Nd2O3: finding the sweet spot.

Removal of organic dyes like methylene blue (MB) from industrial effluents serves as potential source of potable water. Photocatalytic degradation using sustainable catalyst is deemed to be an affordable solution. In this work, Nd2O3/MgO nanocomposite with different compositions (1, 3, and 5wt% Nd2O3 with MgO) have been achieved using hydrothermal synthesis and characterized extensively. Interestingly, increasing Nd2O3 proportion (1-5%) enhances light absorption, and decreases band gap and electron-hole recombination. The efficacy of the photocatalysts is tested with the degradation of MB dye, through optimizing Nd2O3/MgO proportion, contact time, catalyst dose, and pH. Interestingly, control experiments reveal that 5wt% Nd2O3/MgO achieve 99.6% degradation of MB in 90min at pH 7, compared to 88.8% with bare MgO under same condition. Kinetic data show that 5wt% Nd2O3/MgO exhibits ca. 3 times higher degradation rate compared to MgO. For the first time, our work enable MgO-based sustainable photocatalyst development with minimum (5wt%) rare-earth combination to achieve excellent photocatalytic degradation performance.

Interlayered double-doped N,P-MXene/ZnIn2S4 Schottky junction composite photocatalyst: Efficient removal of ciprofloxacin and methyl orange from complex wastewater

In this study, N and P were used to double doping MXene to obtain N,P-MXene with increased layer spacing and structural defects. Schottky junction N,P-MXene/ZnIn2S4 photocatalysts with tight interfacial contacts were obtained by in situ growth of flower-like ZnIn2S4 nanosheets. The N,P-MXene interlayer spatial structure facilitates the uniform dispersion of ZnIn2S4 and the exposure of the active site. The formation of the Schottky barrier enables the two closely contacted interfaces to form a carrier transport channel, which accelerates the arrival of the charge carriers on the catalyst surface for REDOX reactions. 50 N,P-MXene/ZIS degraded 86.1 % of CIP and 93.9 % of MO. In addition, after several cycling experiments, it was proved that the photocatalyst had good structure and chemical stability. The photocatalytic mechanism was demonstrated by UPS and radical quenching experiments. N,P-MXene/ZnIn2S4 is not only suitable for pH = 7–11, but also for salt solution wastewater containing higher concentrations of NaCl or KCl. Therefore, the construction of heteroatom doped N,P-MXene/ZnIn2S4 Schottky junction photocatalysts with excellent photocatalytic degradation performance is of profound significance for the treatment of pollutants.

FeOOH Nanosheets Coupled with ZnCdS Nanoparticles for Highly Improved Photocatalytic Degradation of Organic Dyes and Tetracycline in Water.

Developing a low-cost and highly efficient semiconductor photocatalyst for the decomposition of organic pollutants and antibiotics is highly desirable. Herein, FeOOH nanosheets were prepared using a liquid-phase stirring technique and combined with ZnCdS (ZCS) nanoparticles to construct FeOOH/ZCS nanocomposite photocatalysts. The photocatalytic efficiency of the FeOOH/ZCS nanocomposite was evaluated for the decomposition of various pollutants, including rhodamine B, methylene Blue, and tetracycline. The FeOOH/ZCS nanocomposite exhibited significantly higher photocatalytic performance for the decomposition of various organics. Moreover, the optimized FeOOH/ZCS retained more than 90% of its initial photocatalytic activity even after five successful runs. Radical quenching test and electron spin resonance (ESR) analysis revealed that hydroxyl radicals (•OH) play a dominant role for the decomposition of organics. The FeOOH/ZCS Z-scheme heterojunction significantly facilitates higher charge transfer efficiency and the generation of reactive radicals, resulting in excellent photocatalytic degradation performance. This work offers a new approach to synthesis FeOOH-based photocatalyst for the elimination of organics and antibiotics in water.

One-step thermal oxidation synthesis of carbon-doped TiO2 with enhanced photocatalytic activity using CO2 as the carbon source

The study proposed a simplified carbon doping synthesis strategy to enhance the photocatalytic activity of titanium dioxide (TiO2). Utilizing CO2 gas as the carbon source, the material was directly synthesized onto a titanium substrate through a one-step thermal oxidation method. Raman and XPS analyses indicated that with the increase in CO2 partial pressure, the influence of the carbon source was amplified, resulting in carbon doping in a graphite-like structure and the induction of oxygen vacancies. Electrochemical impedance spectroscopy and UV–vis spectra demonstrated that the introduced carbon species acted as a photosensitizer, augmenting the transfer of photogenerated carriers. Photoluminescence spectra suggested that oxygen vacancies could enhance the non-radiative scattering of photogenerated carriers. These two effects synergistically improved the photocatalytic activity of TiO2 significantly, although the degree of enhancement was dependent on the optimized ratio of carbon content to oxygen vacancy content. Only with optimal carbon content and oxygen vacancy levels could the undesired radiative recombination of photogenerated carriers be prevented, ensuring that the energy derived from visible light was effectively utilized to drive chemical reactions. Under these optimal conditions, the TC-O5 and TC-O10 samples exhibited excellent photocatalytic degradation performance of methyl orange under visible light, with degradation rates of 86.27% and 82.54%, respectively, and displayed outstanding cycling stability, with the degradation rate remaining above 90% for three cycles. This method proved to be simple, efficient, and easily operable, offering significant advantages for industrial-scale preparation.

Effect of phase structure of Bi5O7I on the photocatalytic activity of S-scheme AgBr/Ag/Bi5O7I

The synthesis of pure needle-shaped monoclinic-Bi5O7I (m-Bi5O7I) was reached for the first time at pH 12.2 under a hydrothermal condition, using bismuth citrate as a Bi source. To enhance the photocatalytic activity of m-Bi5O7I, S-scheme AgBr/Ag/m-Bi5O7I (denoted as AAmB) was constructed via a photodeposition method. AAmB exhibited excellent photocatalytic degradation performance towards methylene blue (MB) under visible light illumination with apparent rate constants (0.01047 min−1), and it is approximately 4 times higher than that of AgBr/Ag/orthorhombic-Bi5O7I (plate-shaped) (called as AAoB) (0.00267 min−1) prepared at pH 12.5. Besides, the specific surface area of as-constructed AAmB heterojunction (18.5 m2·g−1) was also higher than that of AAoB (1.0 m2·g−1). These results indicate that the phase structure of Bi5O7I influences the morphology and specific surface area of the heterojunction. Furthermore, AAmB showed superior photodegradation activity for other pollutants, such as tetracycline (TC), bisphenol A (BPA), rhodamine B (RhB), etc. When bismuth nitrate was used as a raw material, only o-Bi5O7I was obtained at a wide pH range from 12 to 13, and the photocatalytic performance of the as-constructed AgBr/Ag/o-Bi5O7I heterojunction based on this o-Bi5O7I was notably lower than that of AAmB.

Sulfur vacancy-induced 1T-MoS2 co-catalyst loaded on Zn3In2S6 for simultaneous promoting photocatalytic hydrogen evolution and pollutant degradation

In the field of photocatalytic hydrogen evolution, Zn3In2S6 has caught tremendous attention because of its suitable band gap and outstanding stability. However, the lower number of active sites as well as lower efficiency of photoproduced carrier separation restricted its further application. Introducing co-catalysts and structural defects are effective methods to solve the above problems. In this paper, Zn3In2S6 loaded metal phase MoS2 to construct flower-shaped spherical catalysts 1T-MoS2/Zn3In2S6 (M/ZIS6) with abundant sulfur vacancies. The visible-light-driven photocatalytic hydrogen evolution rate of 2.4 % M/ZIS6 was 8.71 mmol∙g−1·h−1, which far exceeded those of pure Zn3In2S6 (0.80 mmol∙g−1·h−1) and 2.4 % Pt/Zn3In2S6 (3.86 mmol∙g−1·h−1). Moreover, 2.4 % M/ZIS6 simultaneously displayed the excellent photocatalytic degradation performance toward acid orange 7 (AO7) in the hydrogen evolution reaction process. Co-catalyst metal phase 1T -MoS2, abundant sulfur defects, and a large and dense contact interface between 1T -MoS2 and Zn3In2S6 mainly contributed to the enhanced photocatalytic performance of 2.4 % M/ZIS6. This work provided a potential concept to construct efficient photocatalysts with noble metal-free co-catalyst for bifunctional applications.

Preparation of S-C3N4/AgCdS Z-Scheme Heterojunction Photocatalyst and Its Effectively Improved Photocatalytic Performance.

In this study, S-doped graphitic carbon nitride (S-C3N4) was prepared using the high-temperature polymerization method, and then S-C3N4/AgCdS heterojunction photocatalyst was obtained using the chemical deposition method through loading Ag-doped CdS nanoparticles (AgCdS NPs) on the surface of S-C3N4. Experimental results show that the AgCdS NPs were evenly dispersed on the surface of S-C3N4, indicating that a good heterojunction structure was formed. Compared to S-C3N4, CdS, AgCdS and S-C3N4/CdS, the photocatalytic performance of S-C3N4/AgCdS has been significantly improved, and exhibits excellent photocatalytic degradation performance of Rhodamine B and methyl orange. The doping of Ag in collaboration with the construction of a Z-scheme heterojunction system promoted the effective separation and transport of the photogenerated carriers in S-C3N4/AgCdS, significantly accelerated its photocatalytic reaction process, and thus improved its photocatalytic performance.

Sunflower-inspired hydrogel evaporator with mutual reinforcement of evaporation and photodegradation for integrated water management

Solar interface photothermal evaporation is a promising strategy to ensure affordable water production. However, obtaining freshwater from wastewater containing highly concentrated volatile organic compounds (VOCs) is still a high hanker. Here, a polyvinyl alcohol (PVA)-based hydrogel evaporator was developed to mutually reinforce photothermal evaporation and photocatalytic degradation. The vertical structure promoted the rapid transfer of water molecules between the microchannels. Moreover, the solar absorption efficiency can be improved through multiple reflections. Furthermore, introducing polypyrrole (PPy) and MXene@TiO2@g-C3N4 (MTG) heterojunction can not only regulate the interaction force between the polymer network and water molecules to reduce the evaporation enthalpy, but also endow the PVA/PPy@MTG hydrogel with excellent photocatalytic degradation performance. Besides, the first principles simulation indicated that this hydrogel displayed higher binding energy for contaminants than water molecules. Therefore, it can achieve an evaporation rate of ∼3.0 kg m−2 h−1 and energy efficiency of ∼97.2 % under 1-sun, higher than the structure-disordered PVA/PPy@MTG hydrogel. In addition, it can degrade different complex components, especially for highly concentrated VOCs (100 ppm) with an efficiency of >94.2 %, exceeding most of the reported integrated evaporators. This work will pave a potential pathway to design novel evaporation for sustainable water remediation.

Enhanced synergistic performance of g-C3N4/MoS2 with hollow structure for tetracycline photocatalytic degradation in complex environments: Performance and mechanism

The toxicity of antibiotic and heavy metal combined pollutants is greater than single antibiotic, achieving its synergistic removal is the key. In this work, a novel g-C3N4/MoS2 photocatalyst with hollow structure (CN/MS-V-3) was fabricated by one-step solvothermal method. As expected, CN/MS-V-3 showed an outstanding removal efficiency for tetracycline and Cu2+ of 98.49% and 99.90%, respectively. The excellent photocatalytic degradation performance for tetracycline in compound wastewater mainly ascribed to the enhanced visible-light capture ability by hollow structure of CN/MS-V-3, formation 1O2 and ·OH, and the cycle of Cu2+/Cu+ and Mo2+/Mo4+ induced the fast electrons transport. The contamination of Cu2+ in wastewater can play as an accelerator in the CN/MS-V-3 reaction system to improve the degradation performance of tetracycline. DFT results indicated that CN/MS-V-3 heterojunction was formed by combination of side surface MoS2–V and g-C3N4, and the Cu adsorption onto CN/MS-V-3 showed a potential formation of Cu–N and Cu–S bonds. In addition, the tetracycline degradation pathways and evaluation of toxicity of intermediates were also proposed. This work not only provides a promising technology for antibiotic and heavy metal combined contamination removal, but also a clever use of Cu variable valence to accelerate electron cycling to improve the removal performance of the CN/MS-V-3.

Green Synthesis of Metal-Doped ZnO Nanoparticles Using Bauhinia racemosa Lam. Extract and Evaluation of Their Photocatalysis and Biomedical Applications.

A fascinating problem in the fields of nanoscience and nanobiotechnology has recently emerged, and to tackle this, the production of metal oxide nanoparticles using plant extracts offers numerous benefits over traditional physicochemical methods. In the present investigation, ZnO nanoparticles were fabricated from Bauhinia racemosa Lam. (BR) leaves extract with various transition metal (TM) dopants (Ni, Mn, and Co). Plant leaves extract containing metal nitrate solutions were utilized as a precursor to synthesize the pristine and TM-doped ZnO nanoparticles. Structural, functional, optical, and surface properties of the fabricated samples were studied by using physicochemical and photoelectrochemical measurements. The organic pollutants tetracycline (TC), ampicillin (AMP), and amoxicillin (AMX) were used in the photocatalytic degradation assessment of the fabricated samples. Through X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigation, the fabricated nanoparticles wurtzite crystal structure was verified. Moreover, Fourier transform infrared (FT-IR) analysis verified the existence of functional groups in the fabricated nanoparticles. The migration of electrons from the deep donor level and zinc interstitial to the Zn-defect and O-defect is related to the emission peaks seen at 468, 480, 534, and 450 nm in photoluminescence (PL) spectra. Co-ZnO nanoparticles demonstrated potent and excellent photocatalytic degradation performance for TC (91.09%), AMP (87.97%), and AMX (92.42%) antibiotics within 210, 180, and 150 min of visible light irradiation. Co-ZnO nanoparticles also demonstrated strong antimicrobial performance against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Aspergillus flavus, Aspergillus niger, and Bacillus subtilis. Further investigation of in vitro cytotoxic potential against the A549 cell line (IC50 = 24 ± 0.5 μg/mL) utilizing MTT assay and the free radical scavenging performance of Co-ZnO nanoparticles estimated by DPPH assay utilizing l-ascorbic acid as a reference was also performed. Anti-inflammatory potential is also reviewed by comparing it with the standard drug Diclofenac, and the maximum activity was obtained for Ni-ZnO nanoparticles (IC50 = 72.4 μg/mL).

A novel photo-enzyme platform based on non-metallic modified carbon nitride for removal of bisphenol A in water

A nonmetallic composite photocatalyst with 2D/2D structure was prepared by hydrothermal in-situ polymerization and used for the immobilization of cytochrome C (Cyt c). The photo-enzyme coupling system has a very high enzyme load, which can reach 528.29 mg g−1 after optimization. Compared with free Cyt c, Cytc/PEDOT/CN showed better enzymatic activity, stability and catalytic efficiency. Even after being stored at 100 °C for 60 min, the enzyme activity remained at 49.42 % and remained at 57.89 % after 8 cycles. Moreover, Cytc0.5/PEDOT3/CN showed excellent photocatalytic degradation performance in the degradation experiment of bisphenol A (BPA), reaching 68.22 % degradation rate within 60 min, which was 3.9 times higher than that of pure g-C3N4 and 1.61 times higher than that of pure PEDOT3/CN. This study shows that the introduction of conductive polymers is of great significance to the photo-enzyme coupling system and provides a new strategy for the treatment of phenol-containing wastewater.

Highly efficient magnetically separable SrFe12O19 for photo-assisted oxidation of benzylic alcohol derivatives under visible light

The selective oxidation of the Cα−OH group of benzylic alcohols is a crucial process for the conversion of lignin into useful products. In this study, we describe the synthesis and characterization of magnetic strontium hexaferrite, SrFe12O19. The SrFe12O19 nano-powder was produced through coprecipitation at a pH level of 10. The catalyst has been studied using various methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray analysis (EDX), UV–vis diffuse reflectance spectroscopy (DRS), and magnetic field dependence measurements. The study aimed to evaluate the photocatalytic performance of SrFe12O19 in selective oxidation of benzylic alcohols and degradation of methylene blue under visible light. Additionally, the magnetic properties of the catalyst were also investigated. Magnetic properties were also investigated. M-SrFe12O19 with a band near 2 eV, showed excellent photocatalytic degradation performance at ca. 90% of MB under visible light. The photocatalytic degradation activity was evaluated for three cycles, and the results demonstrate that it maintains its photodegradation potency, with significant photo-degradation conversion of 89%, 87%, and 84%. The experiment clearly demonstrated that the reaction kinetics followed a pseudo-first order. The oxidation of benzyl alcohol (BzOH) was successfully carried out over SrFe12O19 in the presence of hydrogen peroxide, a highly effective green oxidant, under visible light. Notably, the experiment results showed a maximum conversion of BzOH, reaching approximately 70%, with absolute selectivity towards benzaldehyde (BzCHO). Furthermore, the yield of aldehyde increases according to the Hammett constant, with the highest yield being obtained for 2-hydroxybenzaldehyde (σ = −0.37). The synthesized M-SrFe12O19 material shows potential as an eco-friendly method for lignin valorization.

Synthesis of core-shell nanostructured SiO2/TiO2 photocatalysts via atomic layer deposition in a fluidized bed with central tube

Fluidized bed atomic layer deposition is an efficient technique for particle coating with precise control over the film thickness and uniformity at the sub-nanoscale. In this study, a fluidized bed with a central tube is designed, where the central tube has two roles: improve fluidization and deliver precursors separately. The synthesis of core-shell structured SiO2/TiO2 nanoparticle catalysts for photodegradation of tetracycline hydrochloride (TC) is carried out using TiCl4 and H2O as precursors at 180 °C under atmospheric pressure. Under the combination of vibration and central tube, the segregation of agglomerate size along the bed height is weakened, and the prepared SiO2/TiO2 nanoparticles show excellent photocatalytic degradation performance: the degradation efficiency on TC is 96% under 300 W xenon lamp irradiation for 60 min. The mechanism of enhanced photocatalytic activity is due to the Ti-O-Si bonds generated at the interface, which increase the ability to absorb sunlight and accelerate the separation of holes and electrons.

Construction of ZnCdS/TiO2 Z-Scheme heterostructure with excellent photocatalytic performance for degradation of norfloxacin

In this study, the binary heterojunction photocatalyst of ZnCdS modified TiO2 nanorod arrays was successfully prepared by hydrothermal method and successive ionic layer adsorption and reaction (SILAR). The ZCST-12 showed high removal efficiency (93.1%) of norfloxacin (NOR) within 90 min. The rate constant Kα was 0.0278 min−1 and the transient photocurrent density of ZCST-12 was up to 63 μA/cm2, which were 3.08 and 3.7 times higher than that of unmodified TiO2. The synergistic effect of ZnCdS and TiO2 broadens the range of light absorption, makes the absorption edge red shift, and greatly improves the light absorption and utilization ability of the material. The ZnCdS/TiO2 Z-scheme heterojunction greatly promotes the separation of electrons and holes and accelerates the carriers transport, preserves the strong redox ability of spatially separated holes and electrons, and effectively improves the photocatalytic performance. This study provides a simple method for preparing ZnCdS/TiO2 heterojunction photocatalyst.

Nano-island-like heterojunction of nitrogen-doped carbon quantum dots anchoring on titanium oxide nano sheets@Cu2O for enhancing visible light-driving photocatalytic degradation of methyl orange

Cu2O and TiO2 are promising for photocatalysis owing to their lower cost and excellent performance. Unfortunately, the efficiency of light utilization by Cu2O and TiO2 is still low. Herein, the nano-island-like heterojunction of nitrogen-doped carbon quantum dots anchoring on titanium oxide nano sheets@Cu2O (NCQDs/TNSs@Cu2O) was synthesized through the hydrothermal and chemical precipitation process and its photocatalytic performance was systematically characterized. Benefiting from the unique heterojunction, NCQDs/TNSs@Cu2O exhibited a superior photocatalytic performance. High-resolution transmission electron microscopy showed that NCQDs/TNSs nanoclusters were decorated on Cu2O nanoparticle surface and formed heterojunctions. The UV–Vis-DRS spectra indicated that NCQDs/TNSs@Cu2O exhibited the strong adsorption peaks between 400 and 650 nm. Under simulated sunlight irradiation, NCQDs/TNSs@Cu2O exhibited excellent photocatalytic degradation performance on methyl orange. For example, the degradation was completed within 20 min and the photo-degradation capacity of NCQDs/TNSs@Cu2O remained 90.1 % after four recycling cycles. Furthermore, the potential mechanism for the photo-induced degradation was proposed based on the active substances identified through the electron spin resonance. Conclusively, this study provides a novel perspective on the role of NCQDs and prepares the way for the design of the biomass-based photocatalyst.

Photoinduced RhB-sensitized effect on a novel AgI/BiOCl/biochar photocatalyst to boost its photocatalytic performance for 17α-ethinyl estradiol degradation

In this study, a simple and effective strategy was developed for the synthesis of novel visible-light-active AgI/BiOCl/biochar (AgI/BiOCl/BC) photocatalysts. The addition of rhodamine B (RhB) as a sensitizer was found to considerably enhance the photocatalytic activity of AgI/BiOCl/BC toward the degradation of 17α-ethinyl estradiol (EE2). Furthermore, the incorporation of biochar (BC) into the BiOCl resulted in an increased abundance of free radicals, that could be used for degradation. Additionally, the presence of BC facilitated the separation of carriers by serving as an electron transport channel. The photocatalytic efficiency of the AgI/BiOCl/BC photocatalyst was shown to be highly effective in the degradation of EE2, the degradation efficiency of the AgI/BiOCl/BC was found to be 98.60 % after a 12-min exposure to visible light. Additionally, the photocatalytic activity increased further when RhB sensitization was performed, resulting in a remarkable elimination efficiency of 99.60 % for EE2 after only 4 min of photocatalysis. RhB could not only provide photosensitivity but also degrade along with EE2 as a pollutant, which can be used for the treatments of dyes and EE2 wastewater. The results of photocatalysis investigations indicated that AgI/BiOCl/BC could degrade various dyes, including methyl orange (MO), methylene blue (MB), and congo red (CR). Through the introduction of Ag-based materials, the obtained AgI/BiOCl/BC photocatalyst exhibited significant antibacterial potential against Staphylococcus aureus and Escherichia coli, with antibacterial rates of 99.94 % and 99.99 %, respectively. The cyclic experiment demonstarted that AgI/BiOCl/BC exhibited excellent stability and recyclability. Furthermore, the potential photocatalytic mechanism and degradation pathway were suggested through a combination of experimental findings and theoretical investigations. The obtained AgI/BiOCl/BC photocatalyst is a multifunctional photocatalyst with excellent performance in photocatalytic degradation and sterilization. This photocatalyst is expected to be applied to the treatment of complex pollutant water in the environmental field.

Photocatalytic Performance and Degradation Pathways of Z‐Scheme BiO2−X−Ag3PO4 Photocatalysts with Oxygen‐Deficient Structures

AbstractIt is a practical way to raise the efficiency of photocatalysis by using oxygen vacancy defect modified materials. In this experiment, a Z‐scheme BOA composite photocatalyst with defect structure was prepared by hydrothermal in situ precipitation method. The optimal ratio of 1.5 BOA showed excellent photocatalytic degradation performance for MO, TC and CIP under visible light irradiation, and maintained good structural stability and circulation rate after five cycles. The increased photocatalytic activity of the composite can be explained to the heterojunction interface‘s synergistic effects and the quicker electron hole transit rate caused by the surface oxygen vacancy defect. XPS and EPR confirmed the existence of anoxic structure in the composite, PL and photocurrent confirmed the high electron hole transfer rate. The active species that contributed to the degradation process were validated by the active species capture experiment and ESR. LC–MS speculated the possible degradation path of CIP. Finally speculated the reaction mechanism of Z‐scheme BOA composite photocatalyst. Using the anoxic structure of BiO2−X to form a Z‐scheme heterostructure with Ag3PO4, the oxygen vacancy as the electron capture center and active site is conducive to improving the photogenerated electron transfer rate, thereby improving the structural stability and photocatalytic performance of the complex.

Fabrication of oxygen-rich vacant 3D Zn–CuBi2O4/MMT photocatalysts and the enhancement of its photocatalytic performance

Semiconductor catalytic materials have excellent photocatalytic degradation performance for organic pollutants, and photocatalytic degradation is considered to be the most promising technology for environmental pollution treatment. Bismuth-based bimetallic oxide CuBi2O4 is widely recognized as one of the most valuable and promising semiconductor photocatalytic materials because of its narrow bandwidth, strong visible light absorption and excellent chemical stability. To further improve the photocatalytic activity of CuBi2O4, the Zn-doped CuBi2O4/montmorillonite composites were prepared by employing a synergistic control strategy of doping and oxygen vacancies (OVs), which efficiently regulated the electronic structure and the number of active sites to achieve a rapid separation of photogenerated charges. The doping of zn2+ significantly increased the quantity of oxygen vacancies in the prepared materials. The BET revealed that the incorporation of montmorillonite (MMT) greatly increased the specific surface area of CuBi2O4. The experimental findings indicated that 5 % Zn–CuBi2O4/MMT0.6 possessed abundant oxygen vacancies and longer fluorescence lifetime, resulting in better photocatalytic performance. The removal rate of butyl xanthate was 99.31 % in 40 min, and the removal rate of tetracycline hydrochloride (TC) was 93.17 % in 180 min. The 5 % Zn–CuBi2O4/MMT0.6 could effectively inhibit e−/h+ complexation and provide richer catalytic active sites by doping to construct a flower-like oxygen-rich vacancy defect structure, which significantly improves its catalytic performance. The results of the cycling experiments showed that the stability and reproducibility of the 5 % Zn–CuBi2O4/MMT0.6 composites were excellent, the present study provides an innovative idea for the development of efficient and stable visible light photocatalytic applications.

A two-fold interpenetrated Zn(II) organic framework based on mixed ligands: Synthesis, crystal structure, and properties

A new zinc(II) metal organic framework has been obtained from the solvothermal assembly of 1,3,5-benzene tricarboxylate and 1,3-bis(imidazole)propane with zinc nitrate in DMAc–H2O (DMAc is N,N-dimethylacetamide), namely {[Zn2 (μ2-OH)(1,3-BIP)(BTC)]·DMAc·2H2O}n (SNUT-6). The product is characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and elemental analysis. The single-crystal X-ray diffraction reveals that SNUT-6 exhibits a 3D→3D two-fold interpenetrating framework. Furthermore, SNUT-6 demonstrates a highly efficient turn-off fluorescent detection ability for aniline in methanol and shows high sensitivity with a Ksv value of 4.771 × 104 M−1. It also shows excellent photocatalytic degradation performance for a three-dye molecular model: rhodamine b, methyl orange, and methyl blue.

Facile synthesis of nitrogen vacancy-enriched polymeric carbon nitride via the trace manganese-induced precursor recrystallization process for photocatalytic degradation

A nitrogen vacancy-enriched polymeric carbon nitride (MNCN-1) is successfully prepared by one-step thermal polymerization of 3-amino-1,2,4-triazole crystals obtained by the recrystallization process induced via trace manganese species in this study. With a small amount, natural pH and anionic coexist conditions, MNCN-1 shows excellent performance in photocatalytic degradation of RhB, and it also shows good removal of antibiotic contaminants. Several analytical techniques results illustrate that the induction of trace manganese species facilitates the formation of nitrogen vacancies, and the nitrogen vacancies play a significant role in optimizing band structure and inhibiting the recombination of photo-generated carriers. MNCN-1 owns the maximum abundance of nitrogen vacancies. The increased N-vacancies cause a negative shift of the conduction potential, thus enhancing the thermodynamic driving forces and the kinetic of active radical generation. The much stronger reduction capability, increased involvement of trapped electrons in the ORR reaction and more abundant reaction centers for O2 molecules make the N-vacancy-enriched MNCN-1 achieve enhanced radicals’ generation through a two-step single-electron reduction reaction (O2 → •O2-→ H2O2). This study expands the strategy of constructing nitrogen-rich vacancies in polymeric carbon nitride, and elucidates the mechanism of its defective structure in enhancing the photocatalytic activity of PCN.